Vibration is produced by moving parts of machinery due to causes like unbalance, misalignment of shafts and worn out bearings. Every machine has reasonable levels of vibration that are characteristic of its operation. Excessive levels of vibration indicate machine problems which may lead to unsatisfactory operation and eventual breakdown.
Machine malfunction can sometimes be detected by a change in the vibration pattern of that machine. In today's plants where machines are complex and/or large in number, engineers rely on more advanced methods of identifying abnormal levels and patterns of vibration in order to determine the condition of a machine. It is now common to measure the level and rate of the vibrations of machines and use this data to determine which machines require servicing. This monitoring technique is called predictive maintenance.
To properly employ predictive maintenance, vibration data is typically taken and recorded on a scheduled basis during normal use of the machinery. There are a number of systems available for this purpose. Many of such systems are designed around a pool of portable data collectors. Each individual data collector is designed to be transported to a machine to be tested. Vibration data from the machine is collected, and the vibration data is subsequently uploaded to a host computer. The host computer analyzes the vibration data in order to provide a system operator with complex diagnoses. See, for example, U.S. Pat. Nos. 4,885,707 and 4,612,620.
Although such conventional systems have been useful in the past, there have been a number of drawbacks associated with such systems. For example, the portable data collectors have been limited in their ability to analyze the vibration data locally. The system host computer was required to carry out complex analysis of the data subsequent to receiving the data from the data collector. This could result in analysis delays, and could further result in missed opportunities for avoiding impending machine failure.
Furthermore, such conventional systems have tended to rely heavily on the host/client relationship between the host computer and the individual data collectors. In addition to performing the complex data analysis, the system host computer was required to provide schedule information and/or lists of machines which require predictive maintenance to the individual data collectors. If the system host computer were to fail for any reason, the predictive maintenance system as a whole could be effectively shut down. In addition, there may be instances where a communication link between the host computer and one or more of the data collectors cannot be established (e.g., due to limited accessibility to telephone lines, failed communications equipment, etc.). The dependency on a system host computer thus becomes an impediment to a smoothly functioning system.
Portable data collectors also have required considerable labor costs in the past. Several man hours are spent visiting different sites and collecting vibration data from the machines at each site. When problems are detected, oftentimes service personnel and/or more experienced data collector operators must be dispatched to the particular site to determine if in fact there are problems. Again, several more man hours can be lost which may otherwise be attributable to operator error in the original collection of data.
Some "on-line" systems have been developed recently which allow for data to be collected from machines via permanent wiring. Such systems at least partially eliminate the need for portable data collectors. Nevertheless, the systems provide little more than on-line data collection and in some instances, failure probabilities. Analyses of the data and/or advanced diagnoses based on the data are reserved typically to some central location such as the system host.
In view of the aforementioned shortcomings associated with conventional data collectors and systems, there is a strong need in the art for a data collector and system which is no longer dependent on a system host computer or portable data collectors. There is a strong need for a system which is capable of performing its own complex analyses of vibration data. Moreover, there is a strong need for a system which can operate without a system host.